Spinal injury in underbody blast

Improvised Explosive Device (IED) is common in insurgent conflict as such devices are cheap, available, and devastating. Recent literature shows that victims of these devices often have complex injuries including spinal fractures. However, spinal injuries are not described in detail, so the mechanism and effects of these injuries are not well understood. This thesis reviews the literature with respect to spinal injuries in blast and compares it to UK military victims of IED attacks with spinal fractures. In the UK population, the majority of spinal fractures are thoracolumbar and are associated with multiple other injuries. This thesis shows that, based on the patterns of injury in UK blast victims, most fractures are caused by a combination of axial loads and flexion, with the apex of the thoracic spine and the thoracolumbar junction most affected by flexion. Military vehicles incorporate features intended to reduce the effect of blast on their occupants, and a standardised test has been established to evaluate such designs. However, the simple model of the spine used for these tests lacks validity. Understanding the behaviour of the spine in blast incidents will support development of an improved injury prediction model for future vehicle design. In this thesis an in vitro study develops a model to understand the role of posture in shaping fracture patterns when the spine is loaded at the rates seen in blast, and supports the mechanistic propositions this thesis makes about the behaviour of the spine in underbody blast. The clinical outcome and functional effect of blast related spinal fractures is unknown. In a short case series, this thesis suggests that spinal fractures lead to significant pain but the effect of spinal injuries on function is unclear as these victims also have other severe injuries.